JPH0248828Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] The invention relates to cameras, and more specifically, it extracts video signals from photographic images obtained by developing exposed photosensitive film and uses them to produce magnetic sheets, etc. The present invention relates to a photographic camera suitable for photographing with the intention of recording data on another recording medium, reproducing a video signal from the recording medium, and displaying an observation image related to the photographic image on a CRT screen.

[Prior art]

Recently proposed electronic still cameras use, for example, magnetic sheets standardized as still video floppies instead of conventional silver halide photographic film (hereinafter referred to as photosensitive film), and convert photographed images into video signals. Magnetic recording is performed on the magnetic sheet. The magnetic sheet thus obtained is
When applied to a playback device, the video signal is played back. Then, by inputting this reproduced video signal to a television receiver, it is possible to observe images taken with an electronic still camera. Unlike conventional photographic systems, such an image recording/playback system does not require developing the photosensitive film in a dark room or printing after taking pictures, and it is compatible with ordinary television receivers. This method is advantageous in that images can be easily reproduced, and by continuously reproducing a series of still images, it is also possible to reproduce moving images.

By the way, in the above-mentioned electronic still camera, due to cost and weight reduction constraints with current technology, the imaging device used, such as an image pickup tube or solid-state image sensor, is a high-quality image pickup device such as that used in broadcast TV cameras, etc. difficult to use. Therefore, in order to put the above-mentioned electronic still camera system into practical use, problems remain in terms of resolution and image quality.

One method proposed by the applicant in order to solve this problem is to form a photographic image on a photosensitive film using a conventional photographic system that is sufficiently satisfactory in terms of resolution and image quality, and then use a professional The video signal is re-recorded onto a magnetic sheet by a photoprocessor (eg, a traditional DPE processor may perform this task) using high quality imaging equipment. If a video signal is reproduced from the magnetic sheet thus obtained, a fairly high-quality image can be observed on a television receiver. According to this method, not only can high-quality images be reproduced on a television receiver even when images are simply taken using a conventional photo camera, but also the photographic images can be converted into electronic still images. By recording on a magnetic sheet of the same format as the camera system, it is convenient because the image can be reproduced by a common reproduction system.

By the way, in order to extract a video signal from a photographic image recorded on a photosensitive film, a method similar to that used in conventional photographic systems is used to print a photographic image on a negative film onto photographic paper. . That is, instead of placing a photographic paper on a projected image plane obtained by illumination from a light source, a video signal is extracted by arranging the imaging plane of an imaging device and capturing the projected image. However, when capturing a projected image in this way, the imaging light amount must be within a predetermined range determined by the imaging device. Since the imaging time per frame is limited to (1/60) seconds, it is not possible to adjust the time, so the brightness of the projected image itself must be adjusted. Of course, if all the photographic images on the photosensitive film are taken with proper exposure, then by appropriately setting the brightness of the light source that illuminates them, a projected image with proper brightness can be obtained. Therefore, there is no problem, but when a photosensitive film photographed by an ordinary photographer is developed, the reality is that there are variations in image density for each photographed frame.

Taking these circumstances into consideration, we use a slightly high-intensity light source in advance, and when projecting a properly exposed photographic image, we make sure that the illumination is passed through an ND filter with medium transmittance, so that it can be projected onto the photosensitive film. When the image density is high, the transmittance of the ND filter is lowered, and when the image density is low, the transmittance of the ND filter is increased.
It is possible to extract video signals even when the exposure conditions at the time of photography are poor.

However, as the exposure conditions for taking photographs on photosensitive film become worse, it may become impossible to extract video signals from such photographic images. In other words, when the density of a photographic image is low, it can be adjusted over a considerable range by further inserting an ND filter, but when the image density is high, the illumination light source itself can be adjusted to increase the amount of illumination light. I have to increase the brightness. However, the reality is that there are limits to the size and brightness of the light source that can be used, so there are cases where the brightness of the projected image cannot be adjusted within an appropriate range. For example, if a negative film is used as the photosensitive film and the negative density becomes extremely high due to overexposure, it may become impossible to obtain a projected image with a predetermined brightness due to the ability of the illumination light source. Note that when a reversal film is used, this corresponds to when the photograph was taken with underexposure.

In this way, when extracting a video signal from a photographic image recorded on a photosensitive film, the exposure conditions at the time of shooting with a photographic camera affect the post-processing, and in some cases it may be difficult to obtain a satisfactory video signal. There will also be a situation where it becomes impossible to do so.

[Purpose of invention]

The present invention was devised in view of the background of the above-mentioned prior art, and it allows photographic images taken on a photosensitive film to be transferred to a so-called device such as a general television receiver.
It is an object of the present invention to provide a photographic camera capable of photographing under exposure conditions on the premise that a video signal is extracted from a photographic image on a photosensitive film when photographing with the intention of observing through a CRT. .

[Structure of the idea]

In order to achieve the above object, the photographic camera according to the present invention has two photographic modes: one intended for so-called normal post-processing such as slide projector and print processing, and the other intended for reproduction and observation of photographic images using a CRT. Two photographing modes can be switched and used, and exposure adjustment is performed according to each set photographing mode.

[First example]

FIG. 1 shows a 35 mm full-size camera to which the present invention is applied, and a JIS:135 type negative film is loaded in the camera body 1 as a photosensitive film. In this case, each time the shutter button 2 is operated, one frame is sequentially photographed on a roll of negative film. During this photographing process, the automatic exposure control device 4 adjusts the shutter speed according to the external light brightness measured by the photoreceptor 3, so that in most cases the photographing is performed with approximately the appropriate exposure amount.

A photographing mode setting section 5 is provided on the top surface of the camera body 1. This shooting mode setting section 5
is set to index "F" when photographing is performed with the intention of further performing print printing processing after developing the photographed negative film and observing the photographic image from the printed image (hereinafter referred to as "F"). mode). On the other hand, the photographic image obtained by developing the photographed photosensitive film is captured by a video camera, etc., and the resulting video signal is recorded on a magnetic sheet, and based on this magnetic sheet, a television receiver is used. When observing an image, the photographing mode setting section 5 is set to the index "TV" (hereinafter referred to as "TV").
(referred to as "TV" mode). When the shooting mode setting section 5 sets the "TV" mode, the automatic exposure control device 4 adjusts the shutter speed at a level suitable for the "TV" mode.

In FIG. 2, which shows an example of a shutter control circuit used in the above-mentioned camera, the automatic exposure control device 4 includes a well-known integrating circuit consisting of a photoreceptor 3 made of a photoconductive element, an integrating capacitor 6, and the like. , a variable resistor 7 into which exposure control information such as film sensitivity is input, and a control section 8 whose switching level is changed in accordance with the value of the variable resistor 7. In the "F" mode, when the shutter button 2 is pressed, the shutter device 9 is opened and exposure is started, and at the same time, the integrating circuit is activated, and the integration circuit is activated to adjust the brightness of the external light received by the photoreceptor 3. At the appropriate timing, the control section 8 switches to operate the solenoid 10, and the shutter device 9 closes.

The switch 12 is turned on when the photographing mode setting unit 5 is set to the "TV" mode, and a correction resistor 13 is connected in parallel with the photoreceptor 3. Therefore, in the "TV" mode, the charging current of the capacitor 6 becomes larger, and the time it takes to charge the capacitor 6 to the predetermined switching level set in the control section 8 becomes shorter, so the charging current of the capacitor 6 becomes larger than in the "F" mode. The shutter device 9 is closed early, resulting in slightly underexposure.

In this way, when an underexposed negative film is developed, the negative density becomes low and the amount of transmitted light increases. Therefore, as shown in Figure 3,
When a negative film 20 is illuminated by a light source 21 and imaged by a video camera 24 through a lens 22 set at a predetermined projection magnification, an ND with a predetermined transmittance is provided between the light source 21 and the negative film 20. By inserting the filter 23, the amount of light transmitted from the negative film 20 can be freely adjusted.
This means that the video camera 24 can capture an image with an appropriate amount of light. In addition, when adjusting the amount of transmitted light with the ND filter 23, in addition to preparing several types of ND filters with different transmittances and replacing them as appropriate,
A wedge-type ND filter with continuously different transmittances may be used. Also, ND filter 2
3 can also be inserted between the negative film 20 and the video camera 24.

In this way, the video signal obtained from the video camera 24 is subjected to signal processing via the signal processing circuit 25 so as to be compatible with a magnetic disk recording method standardized as a still video floppy, for example, and then processed by the recording circuit 25. is input.
Recording circuit 26 operates magnetic head 28 based on the input video signal. The magnetic head 28 magnetically records the processed video signal onto a magnetic sheet 30 rotated by a motor 29. Then, the recorded magnetic sheet 30
When reproducing an image from an image, the magnetic sheet 30 is rotated under the same conditions as when recording, as shown by the broken line in FIG. After the circuit 33 performs processing to convert the signal into a television signal of the NTSC system, for example, the signal is inputted to a television receiver 34, thereby making it possible to observe the image.

In this manner, when a negative film is used, a slightly underexposed photographic image can be captured by adjusting the amount of light to an appropriate amount without putting a burden on the light source 21. Conversely, when a reversal film is used, for the same reason, the exposure may be slightly over-exposed to lower the density of the photographic image on the film after development. Note that photographic cameras are usually designed to be able to use either negative film or reversal film, and as mentioned above, the direction of exposure adjustment in "TV" mode is reversed depending on the film type. There is. To deal with this, for example, a shutter control circuit as shown in FIG. 4 may be used.

[Second example]

In the shutter control circuit shown in FIG. 4, the second
In addition to the variable resistor 7 shown in the figure, exposure compensation information for the "TV" mode is inputted via a compensation resistor 15 using a variable resistor, so that the switching level of the control section 8 can be compensated. . Then, the DX cord 37 consisting of a plurality of conductive contacts provided on the film cartridge 36 is
It is read out via the DX code detection section 40, and the correction resistor 15 is increased or decreased by a predetermined amount in accordance with this read information. That is, in the "TV" mode, the switch 12 is turned on and the correction resistor 15 is enabled in conjunction with the operation of the shooting mode setting section 5. The correction resistor 15 is adjusted so that the exposure time becomes early when the loaded film is a negative film, and is adjusted so that the exposure time is slightly extended when the loaded film is a reversal film. The density of the resulting photographic images is low and the video signal can be easily extracted by the system shown in FIG. In addition, DX
The variable resistor 7 is also automatically adjusted based on the information read from the code detection section 40.

The illustrated embodiment has been described above, but
For example, it is possible to make changes such as using a digital type automatic exposure control device, or adjusting the aperture of the aperture located in front of the photoreceptor 3 when correcting exposure in "TV" mode. . Furthermore, it goes without saying that the above-described configuration can also be used as is when using a bubble memory or the like as a medium for recording video signals.
As shown in FIG. 4, for cameras equipped with the DX code detection section 40, the "TV"
Exposure correction can be made according to the mode.

[Effect of idea]

As described above, according to the photo camera of the present invention, when the shooting mode is set to "TV" mode, exposure is controlled under conditions that are advantageous when converting a photo image recorded on a photosensitive film into a video signal. This makes it possible to extract video signals in proper conditions from almost all photographic images recorded on photosensitive film, and eliminates dropped frames due to variations in exposure conditions during photographing. Moreover, since the camera using the present invention can be used as is even when using a conventional photographic system, the usage of the photographic camera is expanded and is very convenient.

[Brief explanation of the drawing]

FIG. 1 is an external view of a photographic camera embodying the present invention. FIG. 2 is a circuit diagram showing a first embodiment of the present invention. FIG. 3 is a conceptual diagram showing a system for extracting a video signal from a photographic image, recording it on a magnetic sheet, or displaying the image on a television receiver using the video signal reproduced from the magnetic sheet. FIG. 4 is a circuit diagram showing a second embodiment of the present invention. 1... Camera body, 3... Photoreceptor, 4... Automatic exposure control device, 7... Variable resistor, 9... Shutter device, 12... Switch, 13, 15... Correction resistor, 20... Negative film , 21... light source, 2
3...ND filter, 40...DX code detection section.

Claims (1)

[Claims for Utility Model Registration] (1) In a photographic camera equipped with an automatic exposure control device, which controls the amount of exposure to a photosensitive film, the photosensitive film is a normal photographing mode in which a photographic image obtained through development processing is printed, or the photographic image is optically reproduced to obtain an observation image;
A video signal is extracted from the photographic image and recorded on another recording medium, and one of the shooting modes for CRT display is selected in which an observed image is obtained via a CRT using a reproduced video signal from this recording medium. a shooting mode setting section for
and an exposure amount correction means for correcting the exposure amount so that when the CRT display shooting mode is selected by the shooting mode setting section, the density of the photographic image becomes lighter than when the normal shooting mode is selected. A photographic camera characterized by: (2) The photographic camera according to claim 1, wherein the exposure amount correction means is set to different correction amounts depending on the type of photosensitive film used.